A hybrid active galactic nucleus feedback model with spinning black holes, winds and jets

ABSTRACT We present a hybrid active galactic nucleus (AGN) feedback model that features three accretion disc states (the thick, thin, and slim discs at low, moderate, and super-Eddington accretion rates, respectively), and two feedback modes: thermal isotropic and kinetic jets. The model includes black hole (BH) spin evolution due to gas accretion, BH mergers, jet spin-down, and Lense–Thirring torques. The BH spin determines the jet directions and affects the feedback efficiencies. The model is implemented in the swift code and coupled with the COLIBRE galaxy formation model. We present the first results from hybrid AGN feedback simulations run as part of the COLIBRE suite, focusing on the impact of new parameters and calibration efforts. Using the new hybrid AGN feedback model, we find that AGN feedback affects not just massive galaxies, but all galaxies down to $M_*\approx 10^8$ M$_\odot$. BH spins are predicted to be near-maximal for intermediate-mass BHs ($M_{\mathrm{BH}}\in [10^6,10^8]$ M$_\odot$), and lower for other BH masses, which is in good agreement with observations. The intergalactic medium is hotter and impacted on larger scales in the hybrid AGN feedback simulations compared to those using purely thermal feedback. In the hybrid AGN simulations, we predict that half of the cumulative injected AGN energy is in thermal and the other half in jet form, broadly independent of BH mass and redshift. Jet feedback is important at all redshifts and dominates over thermal feedback at $z\,\lt\,0.5$ and $z\,\gt\,1.5$, but only mildly.